<!DOCTYPE html>
<html lang="zh-CN">
  <head>
    <meta charset="UTF-8" />
    <title>练习2</title>
    <style type="text/css">
      .btn-group button {
        display: block;
        background-color: greenyellow;
        border-color: greenyellow;
        text-align: center;
        width: 40%;
        height: 70px;
      } button:hover{
        background-color:green;
      }
    </style>
  </head>

  <body>
    <h1>垂直按钮组</h1>

    <div class="btn-group">
      <button>Apple</button>
      <button>Samsung</button>
      <button>Sony</button>
    </div>
  </body>
</html>
